340 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1925 



hot air rises, and in order to fill the deficiency the wind sweeps down 

 from the main range. Near our base camp we saw an excellent 

 example of its force. The camp stood in a contracted gorge through 

 which the wind poured down from the mountain to the plain. 

 Kound about the camp were piles of boulders which the Rongbuk 

 •rhicier had (loi)osited in the gorge. These bowklers were remark- 

 ably eroded by the wind. Deep pits and furrows had been eaten 

 into them; they were polished, and broad grooves had been cut into 

 their surface, in places an inch in depth. They were composed of 

 granite and recently deposited, yet from their windward side they 

 looked like lumps of coral while their sheltered surface was ordi- 

 narily smooth. 



Let us see how the animals react to a wind wliich can eat into the 

 granite rock. The mammals are often clothed in thicker coats of 

 hair. We see this in the herds of domesticated goats, delightfid 

 little animals with long hair that hangs down like a kilt around their 

 legs. The Tibetan dogs are often thickly clothed. Sometimes we 

 may see them in the early summer shedding large patches of winter 

 wool. Near Gautsa I saw pigs at 12,000 feet, and they were covered 

 in a thick rusty-colored hair quite different from the half-naked 

 animals of the plains. The Tibetan hare has a dense coat, and it 

 ascends to 17,000 feet. But the ordinary yak is the best example. 

 Next its body is a layer of wool. Over this is a hairy coat which 

 hangs down like an apron from its huge body, especially around its 

 legs. Its neck is provided with a strong mane, and behind it supports 

 a large tail of thick and bushy hair. When the yak is grazing we see 

 the value of this coat. The animals like to feed with their backs to 

 the wind. The thick tail then acts as a kind of wind-proof screen; 

 the long hair around the hind legs adds to the shield, while the head, 

 being kept low, is sheltered by the body and protected above by the 

 hairy mane. 



Everywhere we see the birds adapting themselves to the wind. 

 The little birds escape it by getting behind obstacles. Thus we often 

 see the larks, the finches, the ground choughs feeding on the sheltered 

 side of villages and Avails. When in the open they persistently face 

 the wind ; if they stand across it they may literally be lifted off their 

 feet. The larger birds follow a similar habit. The choughs face 

 the wind when feeding on the pastures; the ravens do likewise when 

 scavenging for refuse; the lammergeyer always heads it when de- 

 scending for bones; the kites persistently come round to windward 

 before swooping down to take garbage "from the ground. Those 

 birds that live around rocks and habitations creep into some shelter 

 when the wind blows. We see the sparrows hiding in the holes of 

 the houses, choughs getting into the lee of rocks, rose finches nestling 



